Foam pump system



Feb 15, 1955 H. v. wlLLl'AMsoN FOAM PUMP SYSTEM 3 Sheets--Sheei'l 1Filed Aug. 27, 1962 ?R0 PDRTIDPHNG VALVE NoZzLE IMS Inventor lclin V.Williamson,

Feb. 15, 1966 H. v. WILLIAMSON 3,234,962

FOAM PUMP SYSTEM Filed Aug. 27, 1962 5 Sheets-Sheet 2 O UT l. E T l N LET 25 ELS 5 60\26 60 sb lf 1o 39 o 27o 9o Inventor' t [cling U.Williamson H'Hrorneg,

Feb. l5, 1966 H. v. WILLIAMSON FOAM PUMP SYSTEM 3 Sheets-Shree?l 5 FiledAug. 27, 1962 Inventor' j'flding V.w|\iarn5on United States Patent O3,234,962 FOAM PUMP SYSTEM l-Iilding V. Williamson, Chicago, Ill.,assigner to Cherrietron Corporation, Chicago, Ill., a corporation ofDelaware Fiied Aug. 27, 1962, Ser. No. 219,540 9 Claims. (Cl. 137-565)This invention relates to a foam producing system for re fightingpurposes. More particularly, this invention is concerned with animproved vane type pump and a control means therefor for produ-sing foamwith large quantities of `water for fighting fires.

The vane type pump as a foam producing mechanism is well known. Itemploys an eccentric rotor mounted in a housing into which water, airand a foam stabilizer are introduced. A homogenous mixture of thesematerials is formed between the rotating vanes which mix and alsocompress the previously mentioned ingredients. While under compressionthe homogenous mixture is moved to the outlet of the pump and therebyreleased under pressure into an adjoining pipe line wherein foam isformed by turbulence of the mixture in its passage to the dischargenozzles. The vane type pump works in a dual capacity as both a mixingand a pumping mechanism. Pumps of this type however, have many drawbacksin their operation. For example, in the pump described in U.S. 2,827,858issued to Hesson, the operation of the pump has no influence on the rateof water flow into the pump. The rate instead is entirely dependent uponthe pressure in the -feed line. This severely limits the flexibility ofinstallation, particularly on truck mounted units since this particularpump has to be mounted at a low level below the water supply tank toeffect a gravitational flow of water to the pump. The rate of water fiowto the pump will vary considerably between the full tank and empty tankoperation since the flow rate is determined by the height of water inthe tank.

Other shortcomings of vane type pumps presently used are their lowtheoretical compressing efficiency. This is necessitated by the factthat they must be capable of operating without damage even though theymay be completely flooded with water. Such designs make it impossible toeiiiciently compress the air portion before discharging the volumetrapped between the blades to the discharge outlet of the pump. When theleading blade reaches the discharge opening in the ordinary vane typepump, the pressure on the trailing blade is still near atmosphericpressure. Pressure lfrom the discharge side thereupon flows vback intothe pump to create full pressure on the trailing blade when it is in thefully extended position. This increases the stress on the blade and alsoincreases the power required to operate the pump. If the discharge portis moved so as to permit precompression, there will Ibe danger of bladebreakage if the Volume between the two blades were completely filledwith noncompressible liquid such as water.

@ther undesirable features of vane type pumps and particularly those inthe pump described in the previously referred to patent, includedexcessive air leakage into the intake portion of the pump due to openend rotor construction having hollow compartments to reduce weight andcost in manufacturing; single speed operation; and relativelycomplicated design due to the nature of the air inlet requirements.

3,234,962 Patented Feb. l5, 1966 It is therefore, an object of thepresent invention to provide an improved vane type pump system whichwill operate at a maximum efficiency.

It is another object of this invention to provide a vane type pumpcapable of drawing in its own water supply so that it can be mounted atany location on a truck without regard to the level of the water supplytank.

It is still another object of the present invention to provide a vanetype pump system wherein the water flow to the pump is limited so thatthe liquid portion will not completely fill the volume trapped betweenthe vanes, thus making it possible to precompress the air portion beforedischarge without danger of breaking the vanes.

Another object is to provide means for controlling the water flow so asto regulate the expansion ratio and also permit operation at differentspeeds and capacities.

Further objects of this invention are to provide a simplified design toreduce the cost of manufacture; to provide maximum capacity for a givensize unit; and also a body housing for a vane type pump which issymmetrical so that the pump is capable of reverse rotation by merelyreversing the direction of the rotor.

The foregoing objects and other objects of the present invention will bereadily appreciated by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawings showing anembodiment of the invention wherein:

FIGURE l is a diagrammatic view of the present foam pump system, showingthe present foam pump operatively connected to a source of water andfoam stabilizer at one side and leading to a bank of nozzles at theother side.

FIGURE 2 is a view in vertical section of the novel foam pump shown inFIGURE l.

FIGURE 3 is a sectional view taken along line 3 3 of FIGURE 2 butshowin-g the pump in a reversed position from that of FIGURE l.

FIGURE 4 is an end View taken along line 4-4 of FIGURE 2.

FIGURE 5 is a top plan View of the pump housing with the manifoldremoved showing the inlet and discharge openings.

FIGURE 6 is a view in vertical section of the rotor assembly shown inFIGURE 3 With the vanes removed and illustrating the hollow compartmentsin the rotor.

FIGURE 7 is a schematic view showing the pump positioned above theliquid supply sources.

Briefly stated, the foam pump system of this invention is comprised ofan improved foam pump and a control means therefor. The pump has achambered housing which accommodates a vaned rotor positioned in aneccentric manner. An inlet and outlet pipe are connected to a unitarymanifold leading to `an inlet and an outlet passage which communicatewith the interior of the housing. The passages are divided by arelatively small wall portion in the housing. As the rotor turns, liquidwith foam stabilizer is drawn under vacuum from a suitable source. Aregulated amount of air is admitted into the liquid to control thevolume of liquid entering the inlet passage. The air is compressed withthe liquid containing the stabilizer and released into the outletpassage. The rotor is positioned in the housing so that the vanes reachtheir maximum extension from the rotor when they are diametricallyopposite the dividing portion of the adjacent passages. Additional airis admitted into the housing through an end plate into the increasingspaces between adjacent rotor blades. The pump is designed so that theleading vane does not reach the outlet passage until substantialcompression of the foam solution is effected and the trailing vane ispartially retracted. A sealed hollow drum is employed to carry the vaneseccentrically around the pump housing.

Proceeding to a detailed description of the present invention, a foampump is shown in FIGURE 1 connected in a fluid tight manner to a watertank 11 and a foam tank 12 by means of pipes or conduits 13 and 14,respectively, which lead to a valving device 15 for proportioning thedesired amount of foam stabilizer and water to the intake side of pump10 through pipe 16. An air intake means 17 is disposed in pipe orconduit 16 having an orifice 18 of a predetermined size at the end of arelatively short stand pipe 19. While any proportioning device creatinga slight vacuum is suitable for operating in conjunction with pump 10,that described in applicants copending application Serial No. 163,841,tiled January 2, 1962, is preferred. The output side of pump 10 isconnected to a bank of nozzles 20 through pipe 21.

Referring specitically to FIGURES 2 and 3 of the drawing it will be seenthat pump 10 comprises a generally cylindrical, chambered housing 23with a smooth annular inner surface 24. It is supported by vfour legs 22which are suitably secured to an appropriate surface. Disposed at thetop of housing 23 and contiguous therewith are adjacent inlet and outletpassages 25 and 26, respectively. A common wall 27 separates passages 25and 26 and a partition 27 divides manifold 28 into inlet and outletportions 28a and 23h for communication with inlet and outlet pipes 16and 21, respectively. Manifold 28 is enclosed by a hood 29 as best seenin FIGURE 2. Eccentrically mounted in housing 23 is a rotor 30 keyed toa shaft 31 supported in end plates 32 and 33 mounted on housing 23.Rotor comprises a cylindrical drum 39 with a hub portion 34 and sixequally spaced spokes 35 with hollow compartments 36 between the spokes.Six vanes 37a-f are carried by the six spokes 35 in slots 38 forreciprocal movement in and out of the rotor when it is rotated. Throughcentrifugal force exerted on vanes 37a-f their outer edges aremaintained in slidable engagement with inner surface Z4. As shownspecifically in FIGURE 3, rotor 30 is positioned in housing 23 so thatvanes 37a-f reach their maximum extension when they are diametricallyopposite common wall Z7 of inlet and outlet passages 25 and 26,respectively, as depicted by vane 37d.

Rotor 30 is driven by the rotation of shaft 4t) having a pinion 41 keyedthereto which meshes with gear 42 secured on shaft 31. Gear casing 43encloses pinion 41 and gear 42, as well as portions of shafts 31 and 40.Two antifriction bearing units 44 and 45 are housed in hub portions 46and 47, respectively. Hub portion 46 is disposed in gear casing 43 whilehub portion 47 is secured to end plate 33 by means of cap screws 50. Toprevent liquid from leaking around shaft 31 two sealing units 48 and 49are provided on shaft 31 for contact with the associated surfaces of endplates 32 and 33, respectively.

Referring specifically to FIGURE 4, a curved or substantiallyhorned-shaped opening 51 is provided in end plate 32 so that air will beadmitted between the vanes when they are in a portion of their maximumintake cycle. This is accomplished by having end plate 32 positioned onhousing 23 as it appears in FIGURE 4, in circular alignment. As bestshown in FIGURE 2, air enters the space between gear case plate 53 andend plate 32 through open spaces between the bolting bosses 52. Morewill be said of the position of opening 51, in the operation of the pumpto follow.

In FIGURE 5 it will be seen that inlet and outlet passages 25 and 26,respectively, communicate with the interior of housing 23 by means ofslots 55 and 54, respectively, which extend circumferentially throughhousing 23. With the exception of the two central triangular slots 56and 57, the remaining slots are arranged in an opposing chevron-likepattern. This provides an angular engagement by vanes 37a-f with aconsequent distribution of wear. Intermediary portion 24a divides inletand outlet slots 55 and y54, respectively, and has a relatively smallarcuate distance with respect to the total inner surface 24. This designallows a vane 37a to move from the outlet passage to the inlet passagewithout prolonged contact with surface 24a.

FIGURE 6 illustrates the hollow compartments 36 and 36a in hollow, metaldrum 39 defined by hub 34 and the periphery 58 as well as adjacentspokes 35. Sealing plates 59 and 60 close the ends of compartments 36and 36a. It will be apparent that a substantially hollow metal rotor islighter and consequently will not add appreciably to the weight of atire lighting truck on which it is mounted. This is important to theunit as a whole since the pump must of necessity be made of heavy metal.Plates 59 and 60 serve to prevent air from entering the compartmentsduring the compression cycle of the pump and later leaking out duringthe intake cycle to diminish the needed vacuum. The eliiciency of thepump is thereby increased through the use of these plates and weight iskept to a minimum.

Operation The advantages -of novel pump 10 and its control means whichcomprises the novel foam pump system can best be understood with respectto its operation. It will be seen that ywhen vane 37a is positioned, bymeans of rotor 30, adjacent common wall 27 and between outlet slots 54-and inlet slots 55 that its outer edge is contiguous withthe peripheryof rotor 30. This is best shown in FIG- URE 3. As the rotor is driven inthe direction of the' arrow, and about an axis in parallel relationshipto the axis of inner surface 24, a vane as shown at 37b will begin t0emerge from rotor 30 and simultaneously move across slots 55. When aleading vane passes beyond inlet slots 55 a vacuum is created behind thevane since the volume between the leading vane and the adjacentfollowing vane is constantly increasing. With pump 10 operativelyconnected to the proportioning valve 15, this vacuum will be transmittedto valve 15 to cause it to open and thereby pull a proportioned solutionof foam and water through pipe 16 and into inlet passage 25. The volumebetween two adjacent vanes will continue to increase till they areequidistantly straddling a point from common wall 27. At this point theleading vane will have already begun to retract and the trailing vaneWill have almost reached its maximum extension. This in effect is theintake cycle of the pump. It will be noted that large volumes Iof airare introduced into the increasing spaces through opening 51 in end wall32, which terminates just short of the 180 mark. After a pair of vanesmoves beyond the position of straddling the 180 point the leading vanewill through its contact with inner surface 24 continue to retract intorotor 30 as shown by vane. 37e thereby causing a decrease in the volumeof the spaces and a consequent compression of the air and foamstabilizer. The compression cycle is thereby begun. This compressioncontinues until a leading vane reaches the nearest oncoming portion ofthe outlet passage 26 whereupon the compressed solution will be ejectedout; through slots 54.

By having both the intake and outlet adjacently disposed and with commonwall 27 having a relatively small' arcuate distance full advantage canbe taken of the 360` rotation of the vanes. course determined by thenumber of vanes employed and the extent of the curvature of the inletand outlet passages. In the present pump the arcuate distance of theinlet andl outlet passages are approximately equal and extend ap-`proximately 60 from common wall 27. Pump 10 can, under appropriatecircumstances, thus be run in a clockwise or counter clockwise directionwith no loss in,

The amount of compression is of' efficiency. With vanes 37a-f beingangled in the normal direction of rotation it is preferred that rotor beturned end for end. However, it is not essential that the vanes be soangled, and if they are disposed at a strict tangent, a. mere reversalof direction of rotor 30 is all that is required.

Adding to the efficiency of the present pump is tne factor thatprecompression of the air and water mixture is effected prior todischarge. It can be demonstrated that it takes less energy to compressa given volume of air or other compressible gas than it does to pump asimilar. volume of water or other nonc-ompressible tiuid. A.

higher .eliciency can only be obtained by precompressing the air portionbefore discharging to pump outlet 26. Without precompression vanes Sa-fare exposed to a maximum pressure 'when they are fully extended, thusrequiring more torque for rotation. sion, the vane is not exposed tofull discharge pressure, until it has been partially retracted, thus thetotal torque for rotation is somewhat reduced. This is accomplished in4the present design .by having a vane partially retracted by the timethe leading vane passes over the nearest oncoming portion of outletpassage 26.

An additional and important feature for maximum etiicient operation ofpump 1lb are the control means for introducing water into inlet 2,5. Asstated earlier proportioning valve serves to create a vacuum or apressure drop in inlet line 16 and preferably at about 3 to 4 p.s.i. Byadmitting air through intake means 17 in controllable amounts by meansof orifice 18, the rate of water tiow into the pump can be increased ordecreased. The rate of water flow is related to the vacuum that can becreated by the vanes during the intake cycle. If air is admitted byintake means 17, the vacuum thus created will be less and the rate ofwater tiow will be lower. The proportioning unit is an essential part ofthis arrangement because it maintains the desired vacuum at the pumpinlet even though the head of water in the supply tank may be somewhatabove the pump inlet. Without the proportioning valve 15 the pressure atthe pump inlet may be greater than atmospheric and therefore water wouldflow out of opening 13 rather than air flowing in to reduce the vacuumfor the previously stated purpose. Opening 18 would consequently have noinuence on the rate of water flow into the pump. The pressure drop of 3to 4 p.s.i. created by the proportioning unit 15 is equal to a head ofwater of about six or eight feet. The same effect could thereby beaccomplished if the pump were mounted six or eight feet above the watersupply and the porportioning valve omitted. Any such means for creatinga vacuum in inlet line 16 is what is required.

The present foam system operates with a high degree ot efficiency whenpipe lines 16 and 21 have a 5 inch diameter. This allows for pump 10 tooperate eectively even up to a rate of 600 gpm. A 1/2 diameter fororifice 18 provides for a controlled rate of about 300 gpm. when chevacuum on the intake side of the pump is at 4-5 p.s.i.

It will be recognized that air inlet means 1'7 has a tixed orifice 18for introducing air into inlet line 16 for controlling Water flow. Ifdesired, any other restriction such as a suitable valve could beemployed instead to provide a variable orice to elect immediate changesin the flow rate or to adjust for operational variances.

The foam pump 10 in the present system has been advantageously describedfor use with a control means which includes means to effect a pressuredrop upstream of the pump in conjunction with air inlet 17. This controlmeans can likewise be employed on any suitable positive displacementpump which is designed to pump liquids and to create a vacuum at itsintake portion dtuing the normal operation. For example, the ilow ratethrough a gear or piston type pump can be regulated by the presentcontrol means without the need of varying the speed of the pump.

With precompresln the previous description of the pump control means,air has been introduced into the water through inlet 17. If desired,other gaseous fluids can be employed in place of air, or supplementarythereto, such as carbon dioxide, nitrogen, hydrogen, etc. Other obviousmodifications of the present invention pertain to the introduction ofair or gas into the water. If desired, the means to effect the pressuredrop in the water can be eliminated and the rate of water tiow throughpump 1t) can be controlled by introducting a gaseous material throughinlet 17 at a pressure greater than that of the water in line 16.

Through the use of the lpreviously described control means for pump 10when employed with air inlet 51 the expansion ratio of foam produced canbe regulated for various speeds and capacities of the pump. This is animportant factor since the emergency at hand will dictate to the tireghter the type to be used. For example, where foam is to be employed inspraying an airport runway for an emergency landing, a dry foam isdesired having a high expansion ratio with a low water content since itwill last much longer than a foam having the opposite characteristics. Awet .foam with a high water content and a low ratio of expansion isemployed to light res close at hand such a-s the ordinary gasoline tire.By controlling the amount of water entering pump 10 these desired foamscan be effected irrespective of the speeds and capacities of a pump.

FTGURE 7 isa schematic view in which the reference characters correspondto those employed in FIGURE l with the addition of a prime symbol. Apump 10' is shown to be disposed at a higher elevation than liquidsupply sources contained in tanks 11 and 12. Pipes or conduits 13 and14' lead from the respective tanks 11 and 12 to a proportioning valve15. A pipe or conduit 16 connects the proportioning valve 15 and aninlet passage of the pump 10', and a pipe or conduit 2.1 leads from anoutlet passage of the pump 10 to nozzles like those illustrated inFIGURE l. A gaseous tluid such as atmospheric air is capable of beingadmitted into the pipe 16 through a pipe 19 having a valve 18 whichprovides a variable orice to effect immediate changes in the ilow rateand adjustment for operational variances.

It will thus be apparent that through the present invention there isprovided an improved foam pumping system which atfords maximumefficiency for a vane type pump. The highest degree of compression iseffected yet at the same time breakage of rotor vanes is virtuallyeliminated. Further, there is provided a vane type pump which is easy tomanufacture because of the simple design; lighter in weight than:previously known pumps of this type; and also capable of being operatedwith the same degree of maximum etiiciency in a reverse manner.Additionally, it will be seen that the present invention affords aunique manner of controlling the ow rate through a positive displacementtype pump which also assures that the proper amount of water and air arepresent in the pump for -desired expansion ratios of foam. The ow rate`of a pump can also be regulated without changing its speed and the pumpcan be located relative to a water supply tank without regard to theheight of the supply tank or the level of the water therein.

One embodiment has been described in the specication for the practice ofthis invention. lt will be understood that various modifications withinthe scope of the invention are possible and it is intended that suchmodications and variations be included within the invention as describedherein and defined by the appended claims wherein there is claimed:

1. A foam pump system comprising a pump including a housing, saidhousing defining an inner chamber having an annular inner surface withadjacent inlet and outlet passages opening into said chamber, saidpassages spaced apart by a dividing solid portion in said inner surfacecovering a relatively small arcuate distance, a liquid :supply source incommunication with said inlet passage, means to create a pressure dropbetween said'. liquid supply source and said inner chamber of said,housing, restricting means to admit a controlled amount. of gaseousfluid between said liquid -supply source and. said inner chamber forcontrolling the amount of liquid. drawn into said pump, said pumpincluding a rotor mounted in said housing for rotation about an axis inparallel relationship with the axis of said inner surface and presentingan eccentric surface with respect to said inner surface, a plurality ofvanes carried for rotation with said rotor and reciprocating movementrelative to said rotor to maintain the outer edges of the vanes insliding engagement with said inner surface, means for admitting airfreely into said inner chamber to till the expanding spaces betweenadjacent vanes, said rotor positioned in said housing so that two ofsaid adjacent vanes form a space of maximum volume when they straddle apoint 180 opposite said dividing portion of said inlet and outletpassages, said vanes positioned in said rotor to substantially decreasethe space defined by/ adjacent vanes, said rotor and said inner surfaceof said housing before the leading vane reaches said outlet passage.

2. A foam pump system comprising a pump having a; housing, said housingdefining an inner chamber having an annular inner surface with adjacentinlet and outlet passages opening into said chamber, said passagesspaced apart by a dividing solid portion in said inner surface coveringa relatively small arcuate distance, at least one liquid supply source,a liquid supply line interconnecting said supply source and said inletpassage, a proportioning device designed to create a relatively smallpressure drop between said liquid supply source and said inlet passage,restricting means to admit controlled amount of gaseous fluid into saidliquid supply line for controlling the amount of liquid drawn into saidpump, said pump including a rotor mounted in said housing for rotationabout an axis in parallel relationship with the axis of said innersurface and presenting an eccentric surface with respect to said innersurface, a plurality of vanes carried for rotation with said rotor andreciprocating movement relative to said rotor to maintain the outeredges of the vanes in sliding engagement with said inner surface, meansfor admitting air freely into said inner chamber to till the expandingspaces between adjacent vanes, said rotor positioned in -said housing sothat two of said adjacent vanes form a space of maximum volume when theystraddle a point 180 opposite said dividing portion of said inlet andoutlet passages, said vanes positioned in said rotor to substantiallydecrease the space dened by adjacent vanes, said rotor and said innersurface of said housing before the leading vane reaches said outletpassage.

3. A foam pump system as defined in claim 2 wherein said restrictingmeans includes an air inlet comprising a relatively short stand pipe incommunication with said liquid supply line between said proportioningdevice and said pump.

4. In a foam pump system: a pump including a housing defining a chamber,said housing having an inlet passage and an outlet passage incommunication with said chamber, conduit means for conducting a liquidmixture of water and foam stabilizer to said inlet passage of said pump,said pump having means disposed in said chamber for creating a vacuum todraw the uid mixture from said conduit means, through said inlet passageand into said chamber and for discharging the liquid mixture from saidchamber through said outlet passage under pressure, means for enabling agaseous fluid to be freely admitted into said chamber between said inletand outlet passages, and restricting means to admit a controlled amountof a gaseous fluid into said conduit means for controlling the amount ofliquid mixture drawn into said pump.

5. In a foam pump system: a pump including a housing dening a chamber,said housing having an inlet passage lil) and an outlet passage incommunication with said chamyber, conduit means for conducting a liquidmixture of water and foam stabilizer to said inlet passage of said pump,said pump having means in said chamber for drawing the iluid mixturefrom said conduit means, 'through said inlet passage and into saidchamber by vacuum and for discharging the liquid mixture from saidchamber through said outlet passage under pressure, Jneans for enablinga gaseous fluid to be freely admitted iinto said chamber between saidinlet and outlet passages, and restricting means to admit a controlledamount of a gaseous uid into said conduit means `for controlling theamount of liquid mixture drawn into said pump, said restricting meansincluding a valve.

6. In a foam pump system: a pump including a housing defining a chamber,said housing having an inlet passage :and an outlet passage incommunication with said chamber, an eccentrically mounted rotor in saidchamber, a plurality of vanes carried by said rotor, and means forenabling the admission of a gaseous fluid into said charn- `ber betweensaid inlet and outlet passages, means for proportioning two liquids,conduit means leading from xtwo liquid supply sources to saidproportioning means and from said proportioning means to said inletpassage of :said pump, and restricting means to admit a controlled.amount of a gaseous fluid into said conduit means for controlling theamount of proportioned liquids drawn into said pump.

7. In a foam pump system: a pump including a housing defining a chamber,said housing having an inlet passage and an outlet passage incommunication with said chamber', an eccentrically mounted rotor in saidchamber, -a plurality of vanes carried by said rotor, and means forenabling the free admission of a gaseous iluid into said Achamberbetween the inlet and outlet passages, means tor proportioning twoliquids, a tank adapted to contain an aqueous liquid, a tank adapted tocontain foam stabil- J'Zer, conduit means in communication with liquidsin -said tanks below the level of said pump and connected to saidproportioning means, conduit means connecting said proportioning meansto said inlet passage of said pump, and restricting means, to admit acontrolled amount of gaseous uid into said conduit means for controllingthe amount of proportioned liquids drawn into said pump.

8. A method of making foam in a foam making system having a water supplysource, a source of foam stabilizer, a pump designed to create a vacuumat its intake portion and a device for proportioning the water and thefoam stabilizer to the pump, the proportioning device effecting apressure drop on the water which passes therethrough, said methodcomprising the steps of: proportioning water and liquid foam stabilizerwhile etfecting a pressure drop on the resulting proportioned water andfoam stabilizer mixture entering the pump and simultaneously controllingthe quantity of proportioned liquid mixture drawn into the pump byadmitting a restricted amount of gaseous fluid into the liquid mixturebetween the proportioning device and the pump, and admitting air freelydirectly into the proportioned liquid mixture in the pump.

9. A foam pump system comprising a pump including a housing, saidhousing defining an inner chamber having an annular inner surface withadjacent inlet and outlet passages opening into said chamber, saidpassages spaced apart by a dividing solid portion in said inner surfacecovering a relatively small arcuate distance, a liquid supply source incommunication with said inlet passage, means to create a pressure dropbetween said liquid supply source and said inner chamber of saidhousing, restricting means to admit a controlled amount of gaseous fluidbetween said liquid supply source and said inner chamber for controllingthe amount of liquid drawn into said pump, said pump including a rotormounted in said housing for rotation about an axis in 9 parallelrelationship with the axis of said inner surface and presenting aneccentric surface with respect to said inner surface, a plurality ofvanes carried for rotation with said rotor and reciprocating movementrelative to said rotor to maintain the outer edges of the vanes insliding engagement with said inner surface, means for admitting airfreely into said inner chamber to ll the expanding space betweenadjacent vanes, said rotor positioned in said housing so that two ofsaid adjacent vanes form a space of maximum volume when they straddle apoint 180 opposite said dividing portion of said inlet and outletpassages, said vanes positioned in said rotor to substantially decreasethe space deined by adjacent vanes, said rotor and said inner surface ofsaid housing before the leading vane reaches said outlet passage,wherein said pressure drop is created by positioning said pump abovesaid liquid supply source.

References Cited by the Examiner UNITED STATES PATENTS 1,614,437 1/1927Cochran 137-625.41 1,804,604 5/1931 Gilbert 103-7 2,480,925 9/1949 Hirst169-14 2,752,934 7/19156 Badberg 169-14 2,827,858 3/1958 Hesson 103-7 X2,887,275 5/1959 Dixon 169-15 X 2,924,178 2/1960 Hogan 103-2 M. CARYNELSON, Primary Examiner.

4. IN A FOAM PUMP SYSTEM: A PUMP INCLUDING A HOUSING DEFINING A CHAMBER,SAID HOUSING HAVING AN INLET PASSAGE AND AN OUTLET PASSAGE INCOMMUNICATION WITH SAID CHAMBER, CONDUIT MEANS FOR CONDUCTING A LIQUIDMIXTURE OF WATER AND FOAM STABILIZER TO SAID INLET PASSAGE OF SAID PUMP,SAID PUMP HAVING MEANS DISPOSED IN SAID CHAMBER FOR CREATING A VACUUM TODRAW THE FLUID MIXTURE FROM SAID CONDUIT MEANS, THROUGH SAID INLETPASSAGE AND INTO SAID CHAMBER AND FOR DISCHARGING THE LIQUID MIXTUREFROM SAID CHAMBER THROUGH SAID OUTLET PASSAGE UNDER PRESSURE MEANS FORENABLING A GASEOUS FLUID TO BE FREELY ADMITTED INTO SAID CHAMBER BETWEENSAID INLET AND OUTLET PASSAGES, AND RESTRICTING MEANS TO ADMIT ACONTROLLED AMOUNT OF A GASEOUS FLUID INTO SAID CONDUIT MEANS FORCONTROLLING THE AMOUNT OF LIQUID DRAWN INTO SAID PUMP.